Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
http://dx.doi.org/ 10.7770/safer-V12N1-art2758
Numerical analysis of cement panels reinforced with
galvanized iron or polypropylene meshes.
Análisis numérico de paneles de cemento reforzados con
mallas de hierro galvanizado o polipropileno.
Sherry Rose Jose, Job Thomas*
Department of Civil Engineering, School of Engineering, Cochin University of Science and
Technology, Cochin, India.
* Author for correspondence, email: [email protected]
ABSTRACT
This paper deals with the numerical analysis of panels reinforced with galvanized
iron (GI) or polypropylene (PP) meshes. It has been a common practice to use galva-
nized iron meshes as reinforcement in panels and is popularly called as ferrocement
panels. Elevated humidity level and presence of salts can lead to corrosion of these gal-
vanized iron meshes, leading to reduced service life. A rust-freepolypropylene mesh can
be used as an alternate to the steel mesh. This paper presents numerical analysis in
ANSYS Workbench based on an experimental study published in the literature” Compara-
tive study of ferrocement panels reinforced with galvanized iron and polypropylene
meshes”. A total of 16 rectangular panels tested in flexure was analyzed. Out of 16 pan-
els, 8 were reinforced with GI mesh and 8 with PP mesh. The specimens were simply
supported on two short edges and subjected to four-point bending. The parameters in-
vestigated include thickness of panels, volume fraction and the material of the mesh. All
the GI mesh panels showed better strength than the corresponding PP mesh rein-
forcedcement panels. However, PP mesh panels exhibited better ductility as compared to
GI mesh panels. An increase of 54% is noticed in 40mm thick panels reinforced with GI
mesh, when compared to 20mm thick panels. Similarly, an increase of 83% is noticed in
40mm thick panels reinforced with PP mesh, when compared to 20mm thick panels. The
results of numerical analysis were found to be comparable with the corresponding exper-
imental results.
Keywords: Flexure, Polypropylene mesh, Galvanized Iron mesh.
Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
http://dx.doi.org/ 10.7770/safer-V12N1-art2758
RESUMEN
Este artículo trata del análisis numérico de paneles reforzados con mallas de hie-
rro galvanizado (GI) o polipropileno (PP). Ha sido una práctica común el uso de mallas
de hierro galvanizado como refuerzo en los paneles y se denomina popularmente como
paneles de ferrocemento. El nivel de humedad elevado y la presencia de sales pueden
provocar la corrosión de estas mallas de hierro galvanizado, lo que reduce la vida útil. Se
puede utilizar una malla de polipropileno libre de óxido como alternativa a la malla de
acero. Este artículo presenta un análisis numérico en ANSYS Work-bench basado en un
estudio experimental publicado en la literatura “Estudio comparativo de paneles de fe-
rrocemento reforzados con mallas de hierro galvanizado y polipropileno”. Se analizó un
total de 16 paneles rectangulares probados en fl exión. De los 16 paneles, 8 fueron re-
forzados con malla GI y 8 con malla PP. Las muestras simplemente se apoyaron en dos
bordes cortos y se sometieron a flexión de cuatro puntos. Los parámetros investigados
incluyen el espesor de los paneles, la fracción de volumen y el material de la malla. To-
dos los paneles de malla GI mostraron mejor resistencia que los correspondientes pane-
les de cemento reforzado con malla de PP. Sin embargo, los paneles de malla de PP ex-
hibieron una mejor ductilidad en comparación con los paneles de malla GI. Se observa
un aumento del 54% en los paneles de 40 mm de espesor reforzados con malla GI, en
comparación con los paneles de 20 mm de espesor. Asimismo, se observa un aumento
del 83% en paneles de 40 mm de espesor reforzados con malla de PP, en comparación
con los paneles de 20 mm de espesor. Se encontró que los resultados del análisis numé-
rico eran comparables con los resultados experimentales correspondientes.
Palabras clave: Flexión, Malla de polipropileno, Malla de hierro galvanizado.
INTRODUCTION
Ferrocement panels are prepared using cement mortar with thin steel wire mesh-
es embedded in it. The reinforcement is generally in the form of two dimensional meshes
or fibers, making ferrocement a homogenous material. The reinforcement can be metal-
lic or non-metallic in nature [1]. The major advantage of using ferrocement is its light
weight and high modulus of rupture compared to concrete. Ferrocement panels are
commonly reinforced with galvanized iron meshes. Elevated humidity level and presence
of salts can lead to the corrosion of galvanized iron meshes, which eventually reduces its
service life. As the diameter of wires is very small, corrosion may lead to complete disin-
tegration of the wire cross-section creating a potential plane of failure. Therefore, arust-
freealternate material, such as polypropylene meshes can be used as a replacement for
galvanized iron meshes to increase the service life of the structure.
Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
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Various researchers have studied ferrocement to investigate its flexural, axial and
punching strength properties. Kulkarni et al. [4] did flexural test on 48 ferrocement pan-
els of size 500 x 200 mm having different thicknesses. It was seen that the ultimate load
and first crack depend on the thickness and the number of reinforcing mesh layers in
ferrocement panels. Another study was carried out by Chandrudu and Desai [5] in which
ferrocement panels of size 970 x 300 x 35 mm were tested under four point bending to
investigate the effect of fly ash on the flexural strength of ferrocement under acidic envi-
ronment. The variables included were mortar quality, number of reinforcing mesh layers,
curing environment and exposure period. It was summarized that 10% addition of fly
ash was the optimum dosage. And it was noticed that an increase in concentration of
hydrochloric acid decreased the flexural strength of ferrocement panels. Ibrahim [6]
studied 27 ferrocement panels each of size 490 x 490 mm for finding the punching shear
capacity. He summarized that the ultimate capacity of panels increased by increasing the
reinforcement ratio and slab thickness. Sakthivel and Jagannathan [7] investigated the
effect of polyvinyl chloride (PVC) coated galvanized iron mesh on the flexural capacity of
ferrocement panels. The panel size was 700 x 200 x 15 mm. Variables comprises num-
ber of reinforcing mesh layers and the configuration of wire mesh. The study briefed that
the PVC coated wire mesh panels exhibit 10% less strength than uncoated GI mesh pan-
els. The Finite Element Method (FEM) projects a calculation method to solve complex dif-
ferential equations. In this paper, experimental results on ferrocement panels are vali-
dated by FE elements software. In the finite element software, experimental objects are
divided into finite elements. In the next step, these elements are assigned with certain
conditions, such as material parameters, support conditions and loads to obtain stress,
displacement and strain distributions of the experiment. Conclusions about the failure, as
well as the stress and crack development in a component can be obtained from evalua-
tion and more detailed analysis.
MATERIAL AND METHODS
The experimental work includes the comparison of flexural responses of GI and PP
reinforced ferrocement panels. Experimental results were taken from literature ”Com-
parative study of ferrocement panels reinforced with galvanized iron and polypropylene
meshes” by A M Ubaid et.al. In the experimental work a total of 16 panels were tested,
each of size 1000x450mm with thicknesses of 20 mm, 30 mm and 40 mm incorporating
2, 3 and 4 layers of GI and PP meshes with square opening. Each specimen was given an
ID based on its thickness, type of mesh and number of mesh layers. For example, 20P-2
means 20 mm thick panel reinforced with 2 layers of PP mesh. Similarly, 40GI-3 means
Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
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40mm thick panel with 3 layers of GI mesh. The PP wire had a tensile strength of 24 MPa
and 2.7mm2 as cross-sectional area. The opening size of PP mesh was 14 mm in both di-
rections. The GI wires had tensile strength of 350 MPa and 0.70mm2 as cross-sectional
area. Specimens were tested using a 1000 kN capacity universal testing machine in dis-
placement control mode at a rate of 2 mm/min. [8].
Fig 1: Panels during casting process
FE ANALYSIS USING ANSYS ANSYS WORKBENCH combines finite element theory
with real world practice. ANSYS is one of the software in finite element analysis (FEA)
used to solve complex engineering problems. The behavior of concrete and reinforced
concrete structures can be analyzed under various loads. The behavior of deformation or
displacement of the body can be observed.
DESCRIPTION OF FEA MODEL: Element solid 186 is used to represent cement
mortar. SOLID 186 is a higher order 3D solid element that exhibits quadratic displace-
ment behavior. The element is defined by 20 nodes. The element can exhibit plasticity,
hyper elasticity, creep, stress stiffening, large deflection and large strain capabilities [9,
10]
Fig 2: FE model of slab with meshes
LINK 180 is used to represent polypropylene mesh and galvanized iron mesh. The
element is a uniaxial tension- compression element with three degrees of freedom at
each node. These include translations in x,y and z directions. It is considered as a pin
Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
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jointed structure; no bending of element is considered. Plasticity, creep, rotation, large
deflection and large strain capabilities are included. The slab modelled using these ele-
ments are shown in figure 1. There are three material properties used in the analysis.
The elastic properties of the materials such as mortar, polypropylene mesh and galva-
nized iron mesh are given in Table 1. The material is assumed to be homogeneous and
isotropic. The stress strain curve of each material is given in figure 3 to figure 5.
Table 1: Material property parameters
Material Parameter Parameter value
Mortar (SOLID 186) Density 2100 kg/m3
Youngs modulus 4000 MPa
Poisson’s Ratio 0.18
Tensile ultimate strength 2 MPa
Compressive ultimate strength 20MPa
Polypropylene
mesh(LINK 180)
Density 855 kg/m3
Youngs modulus 6000 MPa
Tensile ultimate strength 300 MPa
Galvanized iron
mesh(LINK 180)
Density 7800
Youngs modulus 140GPa
Tensile ultimate strength 500 MPa
Fig 3: Stress strain curve of mortar with compressive strength of 20 MPa[11]
Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
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Fig 4: Stress strain curve of polypropylene mesh [12]
Fig 5: Stress strain curve of galvanized iron mesh [13]
Meshing of model is crucial. The shape of finite element decides the accuracy of
calculation. Larger the mesh size of finite elements, less accurate the stresses and
strains calculated in the model. In the present work the mesh size 25mm. Model after
meshing is shown in Fig. 6.
Fig 6: Meshed model of slab
VALIDATION OF TEST DATA
The load deflection responses of four point bending tests were extracted from
software and compared. These load deflection curves are shown in Fig.7.
Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
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Fig 7: Load deformation responses from numerical analysis
RESULTS AND DISCUSSION
Thickness of panel, and the type and number of mesh layers play significant role
in the structural deflection performance of the reinforced cement panels. Displacement
at ultimate load increased with increase in the number of mesh layers for a particular
thickness of panel. When compared to 20mm thick panels, 40 mm thick panels rein-
forced with GI meshes showed a decrease of 68% in deflection and 47% decrease in de-
flection for panels reinforced with polypropylene meshes. This reduction in deflection is
due to the increased thickness of panels. No significant difference in behavior is seen in
panels 20-GI-2 and 20-GI-3 similarly, in panels 20-PP-2 and 20-PP-3. This is because
the middle layer in three-layer panels lies in the neutral axis and hence shows same be-
0
2000
4000
6000
0 20 40 60
Load
(N)
Displacement(mm)
20mm 2 layerPP
GI
EXP PP
EXP GI
0
2000
4000
6000
0 20 40 60
Load
(N)
Displacement(mm)
20mm 3 layerPP
GI
EXP PP
EXP GI
-5000
0
5000
10000
0 10 20 30
Load
(N)
Displacement(mm)
30mm 2 layerGI
PP
EXP PP
EXP GI
0
5000
10000
15000
0 10 20 30
Load
(N)
Displacement(mm)
30mm 3 layerGI
PP
EXP GI
EXP PP
0
5000
10000
15000
0 20 40 60 80
Load
(N)
Displacement(mm)
30mm 4 layerGI
PP
EXP GI
EXP PP0
5000
10000
15000
0 10 20
Load
(N)
Displacement(mm)
40 mm 2 layerGI
PP
EXP GI
EXP PP
-5000
0
5000
10000
15000
0 10 20 30
Load
(N)
Displacement(mm)
40 mm 3 layerGI
PP
EXP GI
EXP PP-5000
0
5000
10000
15000
20000
25000
0 10 20 30 40
Load
(N)
Displacement(mm)
40 mm 4 layerGI
PP
EXP GI
EXP PP
Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
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havior as that of panels reinforced with two layers. Similar behavior is seen in panels
with higher thickness, such as 30mm and 40 mm panels. Ultimate load sustained by
each specimen is tabulated and compared with experimental results in Table 2.
Table 2: Comparison of Ultimate load
Sl
No.
Specimen
ID
Ultimate load(kN) Percentage
Variation Experimental load Pe in kN [8] Analytical load Pa in kN
1 20-GI-2 5.15 5.50 6.79
2 20-PP-2 1.83 2.00 9.28
3 20-GI-3 4.72 4.99 5.72
4 20-PP-3 1.23 1.35 9.75
5 30-GI-2 8.04 8.80 9.45
6 30-PP-2 5.10 5.50 7.84
7 30-GI-3 9.12 9.99 9.53
8 30-PP-3 5.40 5.49 1.66
9 30-GI-4 10.35 11.00 6.28
10 30-PP-4 4.66 4.50 3.43
11 40-GI-2 11.12 11.99 7.82
12 40-PP-2 11.55 12.00 3.89
13 40-GI-3 13.06 13.00 0.45
14 40-PP-3 9.81 10.00 1.93
15 40-GI-4 18.67 19.00 1.76
16 40-PP-4 11.27 12.00 6.47
The GI mesh reinforced panels perform better than the PP mesh panels in ulti-
mate load. The GI mesh panels also showed stiffer behavior than the PP mesh panels as
GI mesh is having higher elastic modulus when compared to PP mesh. An increase of
54% is noticed in 40mm thick panels reinforced with GI mesh, when compared to 20mm
thick panels. Similarly, an increase of 83% is noticed in 40mm thick panels reinforced
with PP mesh, when compared to 20mm thick panels. Thus, it is evident that, ultimate
load carrying capacity of panels increases with thickness of panels. Variation in percent-
age increase in the above case is due to variation in type of reinforcement used. No sig-
nificant difference can be noticed in the load carrying capacity of panels 20-GI-2 and 20-
PP-2 similarly, for panels 20-PP-2 and 20-PP-3. This is because the middle layer in three-
layer panels lies in the neutral axis and hence three-layer panels show the same behav-
ior as that of two-layer panel. Similar trend is seen in panels with increased thickness
such as in case of 30mm and 40mm panels. Variation in analytical results is within ten
Sustainability, Agri, Food and Environmental Research, (ISSN: 0719-3726), 11(X), 2023:
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percentage in all cases. This is due to the unavailability of standard stress strain results
to be inputted in ANSYS software.
As conclusion, total of 16 panels reinforced with GI mesh and PP mesh were mod-
elled and analyzed in ANSYS. The objective of this investigation was to study the influ-
ence of type of reinforcement and number of layers of reinforced meshes. In all cases GI
reinforced panels are superior in structural performance than PP reinforced panels. An
increase of 54% is noticed in 40mm thick panels reinforced with GI mesh, when com-
pared to 20mm thick panels. Similarly, an increase of 83% is noticed in 40mm thick
panels reinforced with PP mesh, when compared to 20mm thick panels. Ultimate load
carrying capacity increased with increase in thickness of panels and number of layers of
reinforcement. However, PP mesh panels exhibited higher ductility than GI mesh panels.
In this study, the variation between the experimental and predicted load is found to be
less than 10 percent. Hence, it can be concluded that the finite element modelling
method used in this study is appropriate to model the reinforced cement panels. It is ex-
pected that the proposed modelling technique can be extended for the study of the effect
of behavior of various other geometrical configurations of reinforced cement panels.
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Received: 03th November 2020; Accepted: 04th January 2022; First distribution: 04th
November 2022.
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